Axially Reciprocating Microsurgical Instrument with Radially Compressed Actuator Handle

ABSTRACT

A microsurgical instrument has a pair of operative surgical surfaces that are moved relative to each other in shearing or grasping procedures performed by the instrument. The instrument has a handle containing an elongate center rod with a ring mounted for reciprocating movement on the rod. A tube is secured to the ring and a shaft extends through the tube and is secured to the rod. The handle also includes a plurality of resilient arms that extend along the length of the rod and engage against a sliding surface of the ring on the rod. The plurality of actuator arms are alternatively manually compressed radially inwardly by the surgeon&#39;s hand and released by the surgeon&#39;s hand to allow the arms to flex radially inwardly and outwardly. The inward and outward movement of the plurality of arms reciprocates the ring on the handle rod and causes the tube and shaft to move axially relative to each other.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention pertains to a microsurgical instrument having apair of operative surgical surfaces that are moved relative to eachother in shearing or grasping procedures performed by the instrument,where the surgical instrument has an actuator handle with actuators thatare radially compressed by the fingers of an operator's hand incontrolling the movement of the operative surgical surfaces.

2. Description of the Related Art

Microsurgical instruments are those types of surgical instrumentsemployed in performing surgical operations on extremely small andextremely delicate parts of the human anatomy, for example the tissuesinside the human eye. There are many different types of microsurgicalinstruments. The more complex in construction are microsurgicalinstruments that have at least one pair of operative surgical surfacesthat move relative to each other when using the instrument. By operativesurgical surfaces what is meant is, for example, the opposed shearingsurfaces of a scissors that have shearing edges that move across eachother in a shearing operation performed by the instrument, or theopposed grasping surfaces of a forceps that move toward and away fromeach other in a grasping operation performed by the instrument. Inmicrosurgical instruments of this type, the scale of the instrument mustbe as small as possible so that the introduction of the instrument tothe surgical site is minimally invasive.

A typical microsurgical instrument is comprised of a manual handle thatis similar in size and shape to a pen or pencil. This enables theinstrument to be easily manipulated by the fingers on one hand of asurgeon. An example of this type of instrument is disclosed in U.S. Pat.No. 5,370,658, assigned to the assignee of the present invention andincorporated herein by reference.

Microsurgical instrument tips of the type disclosed in theabove-referenced patent often comprise a hollow, narrow tube projectingfrom the instrument handle. A narrow fiber or shaft is received in thetube and the shaft and tube are caused to reciprocate relative to eachother in response to manual manipulation of some type of actuator on theinstrument handle. The relative movement between the shaft and tubeoperates the surgical instrument formed at the distal ends of the shaftand tube. Where the surgical instrument is a forceps, the opposed jawsof the forceps are formed at the shaft distal end and moving the tubeover the shaft or retracting the shaft into the tube causes the forcepsjaws to move toward each other. The reverse movements of the tube andshaft cause the jaws to separate from each other. Where the surgicalinstrument is a scissors, one of the shear surfaces is formed at thedistal end of the shaft and the other shear surface is formed at thedistal end of the tube. Moving the tube distal end toward the shaftdistal end causes the shear surfaces and their shearing edges to movetoward and across each other.

As stated earlier, for microsurgical applications, the surgicalinstruments discussed above must be manufactured in an extremely smallscale. The small scale of the microsurgical instrument results in theoperative microsurgical surfaces of the instrument moving relative toeach other in response to the slightest movement of the instrumentactuator by the fingers of the surgeon's hand.

SUMMARY OF THE INVENTION

It is therefore desirable that the microsurgical instrument have ahandle that fits comfortably in the surgeon's hand and is easily rotatedor otherwise moved in the surgeon's hand by slight manipulations of thefingers. It is also desirable that the actuator of the microsurgicalinstrument be easily and comfortably operated by the fingers of thesurgeon's hand in any position of the instrument handle in the hand. Itis also desirable that any resistance to the movement of the actuator ofthe surgical instrument be minimized.

The microsurgical instrument of the present invention is basicallycomprised of a surgical instrument head and a handle attached to thehead. The surgical instrument head includes an elongate, narrow tube anda shaft or fiber that extends through the tube. The tube and shaftaxially reciprocate relative to each other. The reciprocating movementsof the tube and shaft produce movements of operative microsurgicalsurfaces of the instrument.

The microsurgical instrument also includes a rod having a length withopposite proximal and distal ends. The surgical instrument head ispositioned at the distal end of the rod.

A ring is mounted on the rod for axially reciprocating movement betweenfirst and second positions of the ring along the rod length. The ring ismovable toward the rod proximal end to the first position of the ring onthe rod and the ring is movable toward the rod distal end to the secondposition of the ring on the rod. A conical surface is provided on thering. The conical surface has a first hardness. In other embodiments ofthe instrument the ring surface could have a convex shape or a concaveshape.

The instrument handle is provided on the rod proximal end. The handlehas a plurality of arms that are circumferentially spaced around therod. There are a plurality of axially extending slots between adjacentarms of the plurality of arms. The plurality of arms extend axially fromthe rod proximal end along the rod to free distal end surfaces of thearms. The free distal end surfaces of the arms have convex surfaces thatare spaced radially outwardly from and surround the conical surface onthe ring. Manually pressing the actuator arms radially inwardly with thefingertips causes the free distal ends of at least some of the arms toengage with and slide over the conical surface on the ring. This in turncauses the ring to move axially on the rod from the first position ofthe ring on the rod toward the second position of the ring on the rod.Releasing the manual force on the actuator arms allows the resilience ofthe arms to move the arms radially outwardly. The arms could also bespring biased to move radially outwardly. As the arms move outwardly aspring on the rod moves the ring from the second position of the ring onthe rod toward the first position of the ring on the rod. This movementof the ring could also cause the ring conical surface to push the armsradially outwardly. The reciprocation of the ring on the rod producesrelative axial reciprocating movements between the tube and shaft of thesurgical instrument that in turn move the operative microsurgicalsurfaces of the instrument. The convex surfaces on the arm distal endsand the conical surface of the ring minimize the areas of contactbetween the arms and the ring and thereby minimize sliding frictionbetween the distal end surfaces of the arms and the ring surface. Inother embodiments the arm distal ends could each have a point thatcontacts the conical surface of the ring or a roller bearing or someother equivalent means of reducing the friction between the arm and thering conical surface. The circumferential positioning of the arms aroundthe ring enables the arms to be manually moved in any rotated positionof the instrument in the surgeon's hands.

In addition, in an embodiment of the instrument, the surface on the ringis constructed of a material having a hardness that is greater than thehardness of the surfaces of the arms engaging the ring. The harder ringsurface resists wear to the surface due to repeated radially slidingmovements of the surfaces on the arms over the surface on the ring.Employing a stainless steel surface or other equivalent low frictionsurface on the ring further reduces friction between the surface on thering and the surfaces on the actuator arms.

Still further, in an embodiment, the exterior surface of each of theactuator arms is configured in a manner that avoids any potentialpinching of the surgeon's fingers between adjacent arms as the arms aremoved radially toward each other by the surgeon's fingers compressingthe arms.

Further features and advantages of the present invention, as well as thestructure and operation of the present invention, are described indetail below with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and form a part ofthe specification, illustrate the present invention and together withthe description, serve to explain the principles of the invention.

FIG. 1 is a front perspective view of the microsurgical instrument ofthe invention.

FIG. 2 is a rear perspective view of the microsurgical instrument of theinvention.

FIG. 3 is a cross-section side view of the microsurgical instrument ofthe invention.

FIG. 4 is a cross-section side view of the microsurgical instrumentrotated 90 degrees from the position of the instrument shown in FIG. 3.

FIG. 5 is an exploded view of the component parts of the microsurgicalinstrument.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The microsurgical instrument of the present invention is operable toaxially reciprocate a tube and shaft of a surgical instrument similar tothe microsurgical instruments disclosed in U.S. Pat. No. 5,370,658 whichis assigned to the assignee of this application and is incorporatedherein by reference. In surgical instruments of this type a narrow,cylindrical shaft or fiber extends through a narrow tube and the shaftand tube are reciprocated relative to each other to produce relativemovement between the operative microsurgical surfaces of the instrument.The shaft can move in reciprocating movements relative to a stationarytube, or the tube can move in reciprocating movements relative to astationary shaft. As described in the above-referenced patent, thoseoperative microsurgical surfaces can be the surfaces of a microsurgicalinstrument such as a scissors or forceps.

The microsurgical instrument 10 of the present invention is shown in afront perspective view in FIG. 1 and a rear perspective in FIG. 2. Thecomponent parts of the instrument 10 are shown in an exploded view inFIG. 5. In the preferred embodiment of the invention, all of thecomponent parts of the instrument 10 to be described are constructed ofa material that is capable of being sterilized, for example stainlesssteel and alloys of titanium or aluminum. However, it should beunderstood that the preferences set forth herein are not intended to belimiting and the instrument of the invention may be constructed from avariety of materials suitable for the purposes herein described.

The base of the microsurgical instrument 10 is an elongate cylindricalrod 12. The rod 12 has opposite proximal 14 and distal 16 ends and acenter axis 18 that defines mutually perpendicular axial and radialdirections relative to the microsurgical instrument 10. External screwthreading 22 is formed on the rod 12 adjacent the rod proximal end 14.As shown in the drawing figures, the screw threading 22 extends from therod proximal end 14 over the exterior surface of the rod 12 toward therod distal end 16, but ends well short of the rod distal end. Anelongate slot 24 is formed radially halfway through the width of therod. The slot 24 extends through the center of the rod 12 from the rodproximal end 14 toward the rod distal end 16, but ends short of the roddistal end. A pin hole 26 extends through the width of the rod 12 andintersects the slot 24. The pin hole 26 is oriented perpendicular to theslot 24 and is located at an intermediate position along the rod length.A portion of the rod exterior surface 28 adjacent the rod distal end 16is necked down. This portion of the rod 28 has a smaller diameter and asmaller circumference than the remainder of the rod exterior surface. Asmall center bore 32 is formed in the rod at the rod distal end 16. Thecenter bore 32 has a center axis that is coaxial with the rod centeraxis 18. The center bore 32 extends from the rod distal end 16 throughthe center of the rod and intersects the slot 24. As the center bore 32approaches the slot 24, the interior diameter of the bore increasesforming an enlarged portion 34 of the bore that intersects the slot 24.

An instrument head 36 is mounted on the rod distal end 16. Theinstrument head 36 has a cylindrical center bore 38 that receives therod necked down portion 28 at the rod distal end 16. The instrument headcenter bore 38 is press fit on the rod necked down portion 28 insecuring the head 36 to the rod 12. Other means of securing the head 36to the rod 12 could also be employed, for example employing adhesives tosecure the head 36 to the rod 12 or making the head 36 an integral partof the rod 12. The instrument head 36 has a bulbous, generally convexdistal end surface 42 that faces toward the rod distal end 16. Acylindrical wall 44 projects axially from the periphery of the headdistal end surface 42 toward the rod proximal end 14. The wall 44 formsa cylindrical cavity 46 in an opposite side of the instrument head 36from the head distal end surface 42.

A straight, narrow elongate tube 52 extends through the rod center bore32 and the instrument head center bore 38. The tube 52 has a narrow,elongate length with opposite proximal 54 and distal 56 ends and acenter axis that is coaxial with the rod center axis 18. In thepreferred embodiment of the invention, the tube 52 has a constructionsimilar to that of a hypodermic needle. The tube 52 is received throughthe rod center bore 32 and the instrument head center bore 38 foraxially reciprocating movements of the tube 52 relative to the rod 12and the instrument head 36. As described earlier, the tube distal end 56forms a part of an operative microsurgical instrument that is similar tothose of the earlier-referenced U.S. Pat. No. 5,370,658.

A rigid, straight narrow shaft 62 extends through the center of the tube52. The shaft 62 has an elongate length with opposite proximal 64 anddistal 66 ends and a center axis that is coaxial with the rod centeraxis 18. The shaft distal end 66 projects a short distance from the tubedistal end 56 and forms the second part of the operative microsurgicalinstrument similar to those of the earlier referenced U.S. patent. Theelongate length of the shaft 62 extends well beyond the tube proximalend 54 and through the rod slot 24 to the shaft proximal end 64. In thepreferred embodiment of the invention, the shaft 62 is straight andrigid such as a length of rigid wire. However, in alternate embodimentsof the microsurgical instrument 10, the shaft 62 can have a differentconstruction, for example the construction of an optic fiber employed asan illumination light source or a laser light source in themicrosurgical instrument 10.

A cylindrical tubular pin 72 extends through the pin hole 26 of the rod12. The pin 72 has an internally threaded center bore with a center axis(not shown) that is perpendicular to the rod center axis 18. A pair ofscrews 74 are screw threaded into the pin center bore in the oppositeends of the pin 72. A shaft hole 76 extends through the pin 72 and isoriented perpendicular to the center bore of the pin. The shaft 62extends through the shaft hole 76. The pin screws 74 are tightened downin the pin center bore at the opposite ends of the pin 72 and engage theshaft 62 between the screws 74 thereby securing the shaft 62 to the pin72. In this manner, the pin 72 secures the shaft 62 relative to the rod12.

With the tube 52 being capable of axially reciprocating movementsrelative to the rod 12 and the instrument head 36 as described above,the tube 52 is also capable of axially reciprocating movements over theshaft 62 secured to the rod. However, as described in the earlierreferenced U.S. patent, the tube 52 could be secured to the rod 12 andthe shaft 62 could be capable of axially reciprocating movementsrelative to the rod 12, the instrument head 36 and the tube 52.

A coil spring 82 is received in the enlarged portion 34 of the rodcenter bore. The coil spring 82 surrounds the tube 52 and the shaft 62extending through the tube. The spring 82 has a distal end 84 thatengages against an interior surface of the rod 12 at the bottom of theenlarged portion of the rod center bore 34. The opposite proximal end 86of the spring 82 is positioned in a part of the enlarged portion 34 ofthe rod center bore 32 that intersects the rod slot 24.

A ring 92 is mounted on the rod 12 for axially reciprocating slidingmovement of the ring 92 over the rod 12. The ring 92 has a hollowinterior bore 94 that extends through the ring 92. The rod 12 extendsthrough the ring bore 94. The ring 92 is movable on the rod 12 towardthe rod proximal end 14 to a first position of the ring 92 on the rod12, and toward the rod distal end 16 to a second position of the ring 92on the rod 12. The ring 92 has a cylindrical base 96 at the ringproximal end. The ring 92 also has a generally conical portion 98 on thedistal end of the ring 92. The generally conical portion 98 of the ring92 has an exterior sliding surface 102. In the preferred embodiment, thesliding surface 102 has a conical configuration. In other embodimentsthe surface 102 could have more of a convex configuration or more of aconcave configuration. The sliding surface 102 on the ring 92 also has afirst hardness. In the preferred embodiment, the sliding surface 102 onthe ring 92 is an exterior surface of the ring itself. In alternateembodiments, the sliding surface 102 on the ring 92 could be a separatecomponent part secured to the generally conical portion 98 of the ring.For example, the sliding surface 102 could be a stainless steel cap or aTeflon surface secured to or applied to the generally conical portion 98of the ring 92. In further embodiments, the entire ring 92 could beconstructed of stainless steel or a material of similar hardness andhaving a similar coefficient of friction. A bar 104 extends radiallyinwardly from the ring conical portion 98 into the ring interior bore94. The bar 104 extends into the slot 24 on the rod 12 and therebyprevents the ring 92 from rotating on the rod 12 as the ring 92reciprocates over the rod 12. A tube hole 106 extends through the bar104. The tube hole has a center axis that is coaxial with the rod centeraxis 18.

The tube proximal end 54 is press fit into the bar tube hole 106 and issecurely attached to the bar 104 and the ring 92. When the ring 92axially reciprocates on the rod 12, the tube 52 axially reciprocatesthrough the rod center bore 32 and the instrument head center bore 38.

A connection collar 112 is screw threaded onto the external screwthreading 22 of the rod 12. The connection collar 112 has an interiorbore and internal screw threading 114 that mates or threads with theexternal screw threading 22 on the rod 12. By turning the connectioncollar 112 on the rod screw threading 22, the axial position of thecollar 112 relative to the rod 12 can be adjusted. The collar 112 has acylindrical exterior surface that is defined by an intermediate portion116 of the surface between a proximal end portion 118 and a distal endportion 122 of the surface. The intermediate portion 116 of theconnection collar exterior surface is necked down and has acircumferential dimension and a diameter dimension that are slightlysmaller than the respective circumferential dimensions and diameterdimensions of the proximal end portion 118 and the distal end portion122 of the connection collar exterior surface.

A locking hub 132 is secured in the connection collar internal screwthreading 114 adjacent the rod proximal end 14. The hub 132 has aninterior bore 134 that extends completely through the hub 132. Theinterior bore 134 has a hexagon configuration defined by an interiorsurface 136 of the locking hub 132 that surrounds the bore 134. The hub132 is constructed of a semi-rigid material, for example a plasticmaterial that is self-threading into the internal screw threading 114 ofa connection collar 112. The hexagon configuration of the hub interiorsurface 136 allows a tool such as an Allen wrench to be inserted intothe locking hub bore 134 to assist in screw threading the hub 132 intothe connection collar internal screw threading 114.

The handle of the microsurgical instrument 10 is comprised of a handlerearward portion 142 and a handle forward portion 144. Although thehandle of the described embodiment is provided in two parts, inalternate embodiments of the instrument 10, the handle could be asingle, monolithic part comprised of the rearward portion 142 and theforward portion 144. Additionally, the handle rearward portion 142 couldbe removable from the handle forward portion 144 to enable use of theinstrument 10 with only the handle forward portion 144 if desired. In afurther embodiment the handle could be comprised of only the forwardportion 144.

The handle rearward portion 142 has a generally cylindrical length withopposite proximal 146 and distal 148 ends. The exterior surface of therearward portion has a smooth, curved configuration designed to fitcomfortably behind the web of the surgeon's hand between the thumb andforefinger. The handle rearward portion 142 has a circumferentialdimension and an exterior diameter dimension at the distal end 148 thatgradually increases as the handle rearward portion 142 extends from thedistal end 148 toward the proximal end 146. At about the midpoint of thelength of the handle rearward portion 142 the circumferential dimensionand exterior diameter dimension begin to decrease as the handle rearwardportion 142 extends toward the proximal end 146. This provides thehandle rearward portion 142 with the comfortably-shaped exterior surfaceshown in the drawing figures that rests comfortably on the surgeon'shand behind the web between the thumb and forefinger.

The handle rearward portion 142 has an interior bore 152 that extendscompletely through the rearward portion 142. The interior bore 152extending from the handle proximal end 146 is defined by a firstinterior surface 154 having a reduced interior diameter. As the interiorbore 152 continues to extend toward the handle distal end 148 from thefirst interior surface 154, the bore becomes larger and is defined by asecond cylindrical interior surface 156 having a much larger interiordiameter dimension than the first interior surface 154. This secondinterior surface 156 extends through the handle to the handle distal end148.

The handle forward portion 144 also has a generally cylindrical lengthbetween a proximal end 162 and a distal end 164 of the handle forwardportion 144. A cylindrical interior bore 166 extends completely throughthe handle forward portion 144. The exterior surface of the handleforward portion 144 has a cylindrical, necked down portion 168 adjacentthe proximal end 162. This portion 168 of the exterior surface isdimensioned to be securely press fit into the second interior surface156 of the handle rearward portion 142 in attaching the handle forwardportion 144 to the handle rearward portion 142. As explained earlier,the press fit connection could enable the handle rearward portion 142 tobe selectively removable from the handle forward portion 144. Instead ofthe press-fit connection, other equivalent connections could be employedsuch as an adhesive connection or a screw-threaded connection. As theexterior surface of the handle forward portion 144 extends from thenecked down portion 168 toward the distal end 164, the exterior surface170 increases in circumferential dimension and exterior diameterdimension to substantially the same as that of the handle rearwardportion 142 at the rearward portion distal end 148. This provides for asmooth transition between the exterior surface of the handle rearwardportion 142 to the handle forward portion 144. As the exterior surface170 of the handle forward portion 144 continues to extend toward thedistal end 164 of the handle forward portion, the circumferentialdimension and exterior diameter dimension of the exterior surface 170gradually increase and provide the handle forward portion 144 with thesmooth and comfortable exterior surface 170 positioned for gripping bythe surgeon's fingertips as shown in the drawing figures. A plurality ofcircumferential serrations 172 are formed in this area of the exteriorsurface 170 of the handle forward portion 144 to enhance the grip of thesurgeon's fingers on the surface. Beyond the serrations 172 the distalend of the handle forward portion 144 is formed with a rounded, convexsurface 174 that curves around the distal end 164 from the handleforward portion exterior surface 170 to the handle forward portioninterior bore 166.

The interior bore 166 of the handle forward portion 144 is defined by afirst cylindrical interior surface 182 that extends through the handleforward portion 144 from the forward portion proximal end 162. At aboutthe mid-point of the length of the handle forward portion 144, thecylindrical interior surface surrounding the interior bore increases toa second cylindrical interior surface 184 having an interior diameterdimension that is larger than the first cylindrical interior surface182. The second cylindrical interior surface 184 extends through theinterior bore of the handle forward portion 144 from the firstcylindrical interior surface 182 to the distal end surface 174 of thehandle forward portion.

The rod 12 of the instrument is secured in the interior bore of thehandle forward portion 144 by the connection collar 112 being press fitinto the first cylindrical interior surface 182 of the handle forwardportion. This attaches the handle to the rod proximal end. Otherequivalent means could be employed in securing the rod 12 in theinterior bore of the handle forward portion 144. Additionally, thehandle could be on the rod as one monolithic piece with the rod or atleast the rod 12 and the handle forward portion 144 could be made as asingle monolithic piece. With the rod 12 secured in the interior bore ofthe handle forward portion 144, the sliding surface 102 of the ring 92mounted on the rod 12 is positioned radially inside and axially alignedwith the distal end surface 174 of the handle forward portion 144.

A plurality of axially extending slots 186 are formed in the handleforward portion 144 at the distal end 148. The axial slots 186 extendalong the length of the handle forward portion 144 from the distal endsurface 174 toward the proximal end 162 of the handle forward portion144. Each slot has a slot end 188 that is axially positioned where thehandle forward portion first cylindrical interior surface 182transitions to the second cylindrical interior surface 184. Theplurality of axial slots 186 form a plurality of resilient actuator arms192 that are circumferentially spaced around the second cylindricalinterior surface 184 of the handle forward portion interior bore. Asseen in the drawing figures, each of the actuator arms 192 formed by theaxial slots 186 has a radial width dimension that is smallest at theslot ends 188 or where the first cylindrical interior surface 182 of thehandle forward portion interior bore transitions to the secondcylindrical interior surface 184. This gives the actuator arms 192 aradially deflecting resilience. The plurality of slots 186 form each ofthe actuator arms 192 with an interior surface defined by the secondcylindrical interior surface 184 of the handle forward portion 144, andan opposite exterior surface of the actuator arm defined by the exteriorsurface 170 of the handle forward portion 144. In addition, each of theaxial slots 186 defines opposite side surfaces of each actuator arm 192.Each of the arm side surfaces have two planar surface portions 194, 196that are positioned at an angle relative to each other. Radially innersurface portions 194 of each of the actuator arms 192 are substantiallyparallel to each other. The inner surface portions 194 of each arm 192intersect or connect with the actuator arm interior surface defined bythe second cylindrical interior surface 184 of the handle forwardportion 144. The radially outer surface portions 196 of each arm connectwith and extend radially outwardly from the inner surface portions 194and connect with the exterior surface 170 of the handle forward portion144. As the radial outer surface portions 196 extend radially outwardlyfrom the inner surface portions 194 toward the exterior surface 170,they merge toward each other. This configuration of the radially outersurface portions 196 increases the circumferential width dimension ofthe axial slots 186 adjacent the exterior surface 170 of the handleforward portion 144. This increase in the circumferential width of theslots 186 adjacent the exterior surface 170 of the handle forwardportion 144 prevents the surgeon's fingers from being pinched in theslots 186 between adjacent arms 192 when the arms 192 are pressedinwardly by the surgeon's fingers.

The rounded, generally convex distal end surface 174 of the handleforward portion 144 is formed by the plurality of slots 186 into aplurality of free distal end surfaces on the plurality of actuator arms192. What is meant by free distal end surfaces is that the armscantilever from the proximal end 162 of the handle forward position 144to the free distal end surfaces 174 and there are no operativeconnections to the free distal end surfaces. In the at rest positions ofthe arms 192 the distal end surfaces are positioned in a common radialplane with the ring surface 102 and radially outwardly from andsurrounding the ring surface 102. When at least some of the arms 192 arepressed inwardly by the surgeon's fingers, the distal end surfaces 174of the pressed arms engage in sliding engagement with the ring slidingsurface 102. In the preferred embodiment of the instrument, the distalend surfaces 174 of the actuator arms 192 are constructed of a materialhaving a hardness that is less than the hardness of the ring slidingsurface 102. In this manner, the sliding movement of the actuator armdistal end surfaces 174 over the ring sliding surface 102 will not weargrooves in the ring sliding surface 102. In addition, the distal endsurfaces 174 on the actuator arms 192 could be separate surfaces addedto the actuator arms 192. However, in the preferred embodiment of theinvention, the distal end surfaces 174 of the actuator arms 192 aresurfaces of the arms. Furthermore, in other embodiments the distal endsurfaces 179 could make point contact with the ring surface 102 toreduce sliding friction, or the end surfaces could have roller bearingsor other equivalent structures that contact the ring surface 102.

With the construction of the microsurgical instrument 10 explainedabove, the instrument 10 can be comfortably held in the surgeon's handwith the reduced diameter intermediate portion of the instrument wherethe handle rearward portion 142 merges into the handle forward portion144 positioned on the web of the hand between the thumb and forefinger.With the surgeon's fingertips gripping at least some of the actuatorarms 192 of the handle forward portion 144, manually compressing thearms 192 will cause the arm distal end surfaces 174 to contact the ringsurface 102 and exert a compressive force on the sliding surface 102 ofthe ring 92. This will cause the ring 92 to move axially over the rod 12toward the rod distal end 16 and the second position of the ring 92 onthe rod 12. This in turn causes the ring bar 104 to move themicrosurgical instrument tube 52 over the microsurgical instrument shaft62. This movement actuates the microsurgical instrument at the distalends of the tube 52 and shaft 62. In the example shown in the drawings,the microsurgical instrument is a microsurgical grasper 198. Inaddition, the movement of the bar 104 compresses the spring 82.

Releasing the manual compressive force on the actuator arms 192 allowsthe resiliency of the arms 192 to move the arms back to their at restpositions and also releases the force on the ring 92 urging the ringtoward the rod distal end 16. This allows the compressed spring 82 topush the ring 92 over the rod 12 toward the rod proximal end 14 and thefirst position of the ring on the rod. The movement of the ring 92 couldalso cause the ring surface 102 to push the arms 192 radially outwardlyto their at rest positions. This movement of the ring 92 on the rod 12also causes the tube 52 to move relative to the shaft 62 and therebyopens the microsurgical surfaces of the grasper 198 formed at the end ofthe tube 52 and shaft 62.

In view of the foregoing, it will be seen that the several advantages ofthe invention are achieved and attained.

As various modifications could be made in the construction of thesurgical instrument of the invention herein described and illustratedwithout departing from the scope of the invention, it is intended thatall matter contained in the foregoing description or shown in theaccompanying drawings shall be interpreted as illustrative rather thanlimiting. Thus, the breadth and scope of the present invention shouldnot be limited by any of the above-described exemplary embodiments, butshould be defined only in accordance with the following claims appendedhereto and their equivalents.

1. A surgical instrument comprising: a rod having a length with oppositeproximal and distal ends and a center axis that extends along the rodlength and defines mutually perpendicular axial and radial directionsrelative to the surgical instrument; a ring mounted on the rod foraxially reciprocating movement between first and second positions of thering along the rod length, the ring being movable toward the rodproximal end to the first position of the ring on the rod and the ringbeing movable toward the rod distal end to the second position of thering on the rod, a surface on the ring having a first hardness; a handleon the rod, the handle having a plurality of arms that arecircumferentially spaced around the rod with there being axiallyextending slots between adjacent arms of the plurality of arms, theplurality of arms extending axially from the rod proximal end along therod to free distal ends of the arms, the plurality of arms havingsurfaces on the free distal ends of the arms that are positioned in asame radial plane as the surface on the ring having the first hardnessand radially outwardly and surrounding the surface on the ring havingthe first hardness, and the surfaces on the free distal ends of the armshaving a second hardness that is less than the first hardness.
 2. Thesurgical instrument of claim 1, further comprising: the surfaces on thefree distal ends of at least some of the arms engaging against thesurface on the ring while the ring reciprocates on the rod between thefirst and second positions of the ring on the rod.
 3. The surgicalinstrument of claim 1, further comprising: the surface on the ring beinga surface of the ring.
 4. The surgical instrument of claim 3, furthercomprising: the entire surface of the ring having the first hardness. 5.The surgical instrument of claim 1, further comprising: the surfaces onthe free distal ends of the arms being surfaces of the arms.
 6. Thesurgical instrument of claim 1, further comprising: the surfaces on thefree distal ends of the arms engaging in a sliding engagement with thesurface on the ring.
 7. The surgical instrument of claim 1, furthercomprising: the handle having a portion that is secured to the rodproximal end, the plurality of arms being monolithic extensions from thehandle portion, and the slots between the adjacent arms extendingaxially from the free distal ends of the arms toward the handle portionbut ending short of the handle portion.
 8. The surgical instrument ofclaim 1, further comprising: the handle being a separate part from therod and having a portion that is attached on the rod proximal end, andthe plurality of arms extend from the handle portion mounted on the rodproximal end and cantilever over the rod.
 9. The surgical instrument ofclaim 1, further comprising: a surgical instrument head on the roddistal end, the surgical instrument head having a center bore with acenter axis that is coaxial with the rod center axis; a surgicalinstrument tube received in the surgical instrument head center bore foraxially reciprocating movement of the surgical instrument tube throughthe center bore, the surgical instrument tube having opposite proximaland distal ends with the proximal end being operatively connected to thering for reciprocating movement of the surgical instrument tube and thering relative to the surgical instrument head and the rod.
 10. Thesurgical instrument of claim 9, further comprising: a surgicalinstrument shaft extending through the surgical instrument tube, thesurgical instrument shaft having opposite proximal and distal ends withthe distal end of the surgical instrument shaft projecting from thedistal end of the surgical instrument tube and the proximal end of thesurgical instrument shaft projecting from the proximal end of thesurgical instrument tube and being secured stationary to the rod.
 11. Asurgical instrument comprising: a rod having a length with oppositeproximal and distal ends, the rod having a center axis that extendsalong the rod length and defines mutually perpendicular axial and radialdirections relative to the surgical instrument; a ring mounted on therod for axially reciprocating movement between first and secondpositions of the ring on the rod, the ring being movable toward the rodproximal end to the first position of the ring on the rod and the ringbeing movable toward the rod distal end to the second position of thering on the rod, and a conical surface on the ring; a handle on the rod,the handle having a plurality of arms that are circumferentially spacedaround the rod with there being axially extending slots between adjacentarms of the plurality of arms, the plurality of arms extending axiallyfrom the rod proximal end along the rod to free distal ends of the arms,and the distal ends of arms each having a convex surface that ispositioned in a same radial plane as the surface of the ring andradially outwardly of the surface on the ring.
 12. The surgicalinstrument of claim 11, further comprising: the convex surface on thedistal end of at least some of the arms engaging in sliding engagementwith the conical surface on the ring while the ring reciprocates betweenthe first and second positions of the ring on the rod.
 13. The surgicalinstrument of claim 11, further comprising: the conical surface on thering being a surface of the ring.
 14. The surgical instrument of claim11, further comprising: the convex surface on the distal end of each armbeing a surface of the arm.
 15. The surgical instrument of claim 11,further comprising: the handle having a portion that is secured to therod proximal end, the plurality of arms being monolithic extensions fromthe handle portion, and the slots between the adjacent arms extendingaxially from the free distal ends of the arms toward the handle portionbut ending short of the handle portion.
 16. The surgical instrument ofclaim 15, further comprising: the handle portion secured to the rodproximal end being an intermediate portion of the handle, and the handlehaving a rearward portion that extends from the handle intermediateportion axially away from the rod proximal end.
 17. The surgicalinstrument of claim 11, further comprising: the handle having a portionthat is mounted on the rod proximal end, and the plurality of armsextend from the handle portion mounted on the rod proximal end andcantilever over the rod.
 18. The surgical instrument of claim 11,further comprising: a surgical instrument head on the rod distal end,the surgical instrument head having a center bore with a center axisthat is coaxial with the rod center axis; a first part of a surgicalinstrument having a first microsurgical surface is received in thesurgical instrument head center bore for axially reciprocating movementof the first part of the surgical instrument through the center bore,the first part of the surgical instrument having opposite proximal anddistal ends with the proximal end being operatively connected to thering for reciprocating movement of the first part of the surgicalinstrument and the ring relative to the surgical instrument head and therod.
 19. The surgical instrument of claim 18, further comprising: asecond part of the surgical instrument having a second microsurgicalsurface, the second part of the surgical instrument extending along thefirst part of the surgical instrument, the second part of the surgicalinstrument having opposite proximal and distal ends with the proximalend of the second part of the surgical instrument being securedstationary to the rod.
 20. A surgical instrument comprising: a rodhaving a length with opposite proximal and distal ends, the rod having acenter axis that extends along the rod length and defines mutuallyperpendicular axial and radial directions relative to the surgicalinstrument; a ring mounted on the rod for axially reciprocating movementbetween first and second positions of the ring on the rod, the ringbeing movable toward the rod proximal end to the first position of thering on the rod and the ring being movable toward the rod distal end tothe second position of the ring on the rod; a handle on the rod, thehandle having a plurality of arms that are circumferentially spacedaround the rod with there being axially extending slots between adjacentarms of the plurality of arms, the plurality of arms extending axiallyfrom the rod proximal end along the rod to free distal ends of the armsthat are radially outward of and surround the ring, each arm having aninterior surface that opposes the rod and an opposite exterior surface,each arm having opposite side surfaces that extend radially between theinterior and exterior surfaces of the arm, and at least portions of theopposite side surfaces of each arm merge inwardly toward each other asthe opposite side surfaces extend radially from the interior surface tothe exterior surface of the arm.
 21. The surgical instrument of claim20, further comprising: the opposite side surfaces of each arm havingportions that are substantially parallel to each other as well as theportions that merge toward each other.
 22. The surgical instrument ofclaim 20, further comprising: the portions of the opposite side surfacesof each arm that merge toward each other connect with the exteriorsurface of the arm.
 23. The surgical instrument of claim 20, furthercomprising: the portions of the opposite side surfaces of each arm thatmerge toward each other are flat surfaces.
 24. The surgical instrumentof claim 20, further comprising: each arm of the plurality of arms hasserrations across the exterior surface of the arm.
 25. The surgicalinstrument of claim 20, further comprising: at least some of the freedistal ends of the arms engage against the ring while the ringreciprocates on the rod between the first and second positions of thering on the rod.
 26. The surgical instrument of claim 20, furthercomprising: the free distal ends of the arms engaging in a slidingengagement with the ring.
 27. The surgical instrument of claim 20,further comprising: each arm of the plurality of arms having a proximalend that is opposite the distal end of the arm and having a radial widthdimension that is smallest at the arm proximal end.
 28. The surgicalinstrument of claim 20, further comprising: the handle having a portionthat is secured to the rod proximal end, the plurality of arms beingmonolithic extensions from the handle portion, and the slots between theadjacent arms extending axially from the free distal ends of the armstoward the handle portion but ending short of the handle portion. 29.The surgical instrument of claim 28, further comprising: the handleportion secured to the rod proximal end being an intermediate portion ofthe handle, and the handle having a rearward portion that extends fromthe handle intermediate portion axially away from the rod proximal end.30. The surgical instrument of claim 20, further comprising: the handlehaving a portion that is mounted on the rod proximal end, and theplurality of arms extend from the handle portion mounted on the rodproximal end and cantilever over the rod.
 31. The surgical instrument ofclaim 20, further comprising: a surgical instrument head on the roddistal end, the surgical instrument head having a center bore with acenter axis that is coaxial with the rod center axis; a surgicalinstrument tube received in the surgical instrument head center bore foraxially reciprocating movement of the surgical instrument tube throughthe center bore, the surgical instrument tube having opposite proximaland distal ends with the proximal end being operatively connected to thering for reciprocating movement of the surgical instrument tube and thering relative to the surgical instrument head and the rod.
 32. Thesurgical instrument of claim 31, further comprising: a surgicalinstrument shaft extending through the surgical instrument tube, thesurgical instrument shaft having opposite proximal and distal ends withthe distal end of the surgical instrument shaft projecting from thedistal end of the surgical instrument tube and the proximal end of thesurgical instrument shaft projecting from the proximal end of thesurgical instrument tube and being secured stationary to the rod.